US8699605B2ActiveUtilityPatentIndex 58
Method and apparatus for receiving in multiple-input multiple-output system
Est. expiryAug 27, 2029(~3.1 yrs left)· nominal 20-yr term from priority
Inventors:YANG JOO YEOL
H04B 7/0854H04L 27/2647
58
PatentIndex Score
3
Cited by
7
References
10
Claims
Abstract
A receiving method and apparatus in a Multiple-Input Multiple-Output (MIMO) communication system are provided. The method includes receiving reception signals through a plurality of reception antennas, grouping symbols corresponding to the reception signals, respectively, into a preset number of groups, and rearranging symbols of the respective groups, transforming the reception signals by applying QR decomposition to the reception signals, sequentially canceling interference due to each of total possible candidate symbols for a first symbol based on an order of the rearranged symbols in the transformed reception signals, determining a portion of the total possible candidate symbols to be a candidate symbol set for each remaining symbol, except for the first symbol, using the interference-canceled reception signal, and determining log-likelihood ratio values of the first symbol, which are to be used upon decoding the received signals, using candidate symbols for the first symbol and each remaining symbol.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1. A receiving method in a Multiple-Input Multiple-Output (MIMO) communication system, the method comprising:
receiving reception signals through a plurality of reception antennas;
grouping symbols corresponding to the reception signals, respectively, into a preset number of groups, and rearranging symbols of the respective groups;
transforming the reception signals by applying QR decomposition to the reception signals;
sequentially canceling interference in the transformed reception signals due to each of total possible candidate symbols for a first symbol based on an order of the rearranged symbols;
determining a portion of the total possible candidate symbols to be a candidate symbol set for each remaining symbol, except for the first symbol, using the interference-canceled reception signal;
determining log-likelihood ratio values of the first symbol, which are to be used upon decoding the reception signals, using candidate symbols for the first symbol and each remaining symbol;
comparing a minimum Euclidean value when each bit of each of the total possible candidate symbols has a value of “1” with a minimum Euclidean value when each bit of each of the total possible candidate symbols has a value of “0,”
determining a symbol vector corresponding to when a lower value of the two minimum Euclidean values as a maximum likelihood hard decision result value; and
determining a log-likelihood ratio of each of the remaining symbols using the maximum likelihood hard decision result value.
2. The method as claimed in claim 1 , wherein the determining of the portion of the total possible candidate symbols to be a candidate symbol set for each remaining symbol comprises:
acquiring a representative signal by performing a slicing operation on the interference-canceled reception signal; and
determining symbols corresponding to at least two constellation points, which are spaced by a shortest distance and by an equal distance from a constellation point corresponding to the representative signal in a pre-defined constellation.
3. The method as claimed in claim 1 , wherein the determining of the log-likelihood ratio values comprises:
determining an Euclidean distance for cases where each bit of each of the total possible candidate symbols has a value of “1” and has a value of “0”; and
determining a difference between minimum values of Euclidean distances for cases where each bit of each of the total possible candidate symbols has a value of “1” and has a value of “0,” thereby determining the log-likelihood ratio of the first symbol.
4. The method as claimed in claim 1 wherein the log-likelihood ratio of each of the remaining symbols is determined by equation below:
L
D
1
(
x
j
,
k
❘
y
)
=
{
y
-
Hx
ML
2
-
min
x
∈
X
k
,
+
1
y
-
Hx
2
if
x
ML
∈
X
k
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-
1
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x
∈
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k
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-
1
y
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Hx
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y
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ML
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x
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,
wherein L D 1 (x j,k |y) denotes an LLR value of a k th bit of x j , x ML denotes the maximum likelihood hard decision result value, y denotes a reception signal vector, H denotes a channel matrix vector, x denotes a symbol vector, k denotes an index of a candidate symbol, X k,−1 denotes a case where a bit of a k th candidate symbol has a value of “1,” and X k,+1 represents a case where a bit of a k th candidate symbol has a value of “0.”
5. The method as claimed in claim 1 , wherein the QR decomposition corresponds to expressing a channel matrix as a product of a Q matrix and an R matrix, which are a unitary matrix and an upper triangular matrix, respectively.
6. A receiving apparatus in a Multiple-Input Multiple-Output (MIMO) communication system, the apparatus comprising:
a reception unit for receiving reception signals through a plurality of reception antennas;
an order rearrangement unit for grouping symbols corresponding to the reception signals, respectively, into a preset number of groups, and rearranging symbols of the respective groups;
a QR decomposition unit for transforming the reception signals by applying QR decomposition to the reception signals;
in the transformed reception signals due to each of total possible candidate symbols for a first symbol based on an order of the rearranged symbols;
a candidate symbol selection unit for determining a portion of the total possible candidate symbols to be a candidate symbol set for each remaining symbol, except for the first symbol, using the interference-canceled reception signal; and
a log-likelihood ratio calculation unit for determining log-likelihood ratio values of the first symbol, which is to be used upon decoding the reception signals, using candidate symbols for the first symbol and each remaining symbol,
wherein the log-likelihood ratio calculation unit compares a minimum Euclidean value when each bit of each of the total possible candidate symbols has a value of “1” with a minimum Euclidean value when each bit of each of the total possible candidate symbols has a value of “0,” determines a symbol vector corresponding to when a lower value of the two minimum Euclidean values as a maximum likelihood hard decision result value, and determines a log-likelihood ratio of each of the remaining symbols using the maximum likelihood hard decision result value.
7. The apparatus as claimed in claim 6 , wherein the candidate symbol selection unit acquires a representative value by performing a slicing operation on the interference-canceled reception signal, and determines symbols corresponding to at least two constellation points, which are spaced by a shortest distance and by an equal distance from a constellation point corresponding to the representative value in a pre-defined constellation.
8. The apparatus as claimed in claim 6 , further comprising an Euclidean distance calculation unit for determining an Euclidean distance for cases where each bit of each of the total possible candidate symbols has a value of “1” and has a value of “0,”
wherein the log-likelihood ratio calculation unit determines a difference between minimum values of Euclidean distances for cases where each bit of each of the total possible candidate symbols has a value of “1” and has a value of “0,” thereby determining the log-likelihood ratio of the first symbol, the Euclidean distances being acquired from the Euclidean distance calculation unit.
9. The apparatus as claimed in claim 6 , wherein the log-likelihood ratio of each of the remaining symbols is determined by equation below:
L
D
1
(
x
j
,
k
❘
y
)
=
{
y
-
Hx
ML
2
-
min
x
∈
X
k
,
+
1
y
-
Hx
2
if
x
ML
∈
X
k
,
-
1
min
x
∈
X
k
,
-
1
y
-
Hx
2
-
y
-
Hx
ML
2
if
x
ML
∈
X
k
,
+
1
,
wherein L D 1 (x j,k |y) denotes an LLR value of a k th bit of x j , x ML denotes the maximum likelihood hard decision result value, y denotes a reception signal vector, H denotes a channel matrix vector, x denotes a symbol vector, k denotes an index of a candidate symbol, X k,−1 denotes a case where a bit of a k th candidate symbol has a value of “1,” and X k,+1 represents a case where a bit of a k th candidate symbol has a value of “0.”
10. The apparatus as claimed in claim 6 , wherein the QR decomposition corresponds to expressing channel matrix as a product of a Q matrix and an R matrix, which are a unitary matrix and an upper triangular matrix, respectively.Cited by (0)
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